Reliability of pressure pain threshold on myofascial trigger points in the trapezius muscle of women with chronic neck pain

OBJECTIVE: The aim of this study was to evaluate the intra- and inter-rater reliability of pressure pain threshold measurement on myofascial trigger points in the trapezius muscle in women with chronic neck pain. METHODS: This reliability study involved 30 volunteers with neck pain for more than 90 days. The assessment procedures were performed by blinded researchers. Two examiners, who were previously trained in the use of algometry, independently performed two assessments of the pressure pain threshold at two time intervals, one week apart. RESULTS: The study sample consisted of 30 young adult women. Excellent intra- and inter-rater reliability were found for the pressure pain threshold on myofascial trigger points, with intraclass correlation coefficient values ranging between 0.752 and 0.874, standard error of measurement ranging between 0.18 and 0.22 kg/cm(2), and minimum detectable change ranging between 0.45 and 0.62 kg/cm(2). CONCLUSION: The present study showed that the assessment of pressure pain threshold through algometry presents satisfactory intraclass correlation coefficient values, considering different time and examiners, contributing to the spread of the use of this tool as a quantitative method of pain evaluation in myofascial trigger points.